With acoustic systems essentially and in particular with hearing devices, a plurality of microphone signals are required to be combined spatially and filtered spectrally such that the output signal has the fewest possible interference components. In this case interferences are defined on the one hand as the signals, which occur due to undesired directions, in this case outside a specific angle range around the 0° direction, e.g. +/−60°, and on the other hand as a microphone noise, which can be amplified particularly in low frequency ranges, during the development of the directional effect. In particular, the problem here is that the microphone noise increases if the directional effect of a directional microphone is increased.